JP6088333B2 - Golf club and manufacturing method thereof - Google Patents

Description

  The present invention relates to a golf club with improved durability and a method for manufacturing the same. More specifically, the present invention relates to a golf club whose durability has been improved by improving the forging method of the face portion of the head of the golf club, and a manufacturing method thereof.

  Various attempts have been made to improve the performance of the golf club within a prescribed range, and there are various forms. Many forged golf clubs have been developed especially using titanium. The face part of the head of the golf club is a part that is hit, and unlike other parts, it requires strength.

  The manufacture of this head includes a casting method in which a metal member is melted and formed, a method in which a plate material is punched into a head shape, and then subjected to press working and formed. Further, there is a forging method in which a material is molded by causing plastic deformation by hot forging or cold forging. When manufacturing a head by forging, for example, an iron head is generally forged from a round bar. As materials for golf clubs, steel materials and titanium materials are mainly used.

  Since the bar is a rolled material, forged lines (metal flow) indicating the rolling direction are generated inside. As for the effect of this forged line, there are known examples in which the face portion is provided for the purpose of reducing the player's discomfort (see, for example, Patent Documents 1 and 2). In this example, a forging line is extended from the neck main body portion toward the toe portion of the face main body portion, and is formed on the face portion. Even if it strikes at a portion other than the sweet spot due to the extension of such a streamline, the player can reduce discomfort.

  As an example of manufacturing a face part of a wood-type head, there is known a forging method in which a titanium alloy bar is forged by setting a predetermined temperature range in two stages (see, for example, Patent Document 3). In this example, the face portion, particularly the score line, is formed by forging to improve the resilience performance and durability, but the configuration of the forging line is not involved. Further, an example of a golf club is known in which a β-type titanium alloy is used for the face portion of the head and hot forging is performed to improve durability and reduce the thickness (see, for example, Patent Document 4).

  According to this example, the titanium alloy is heated and forged and then air-cooled to reduce the β crystal grain size. This example is also forging, but it is not related to forging lines. Further, there is also known an example of a golf club in which a metal material having a fine crystal structure as a metal material is applied to the face portion to reduce the thickness and improve the resilience (see, for example, Patent Document 5). This example is also due to plastic working, but is not related to the forging line.

JP 2009-261909 A JP 2009-261908 A Japanese Patent Laid-Open No. 2004-202098 JP 2004-337445 A JP 2004-305336 A

  As described above, there are many examples of golf clubs in which the face portion of the head is thinned to improve durability. However, there are few examples of forming a golf club head for the purpose of forming forged lines by forging. The above-described conventional example is mainly applied to an iron-type golf club, and is formed integrally with a neck portion, and a forged line is continuously formed in the head and on the surface.

  In this example, the round bar is squeezed, but the round bar is forged from the shape as it is. For this reason, the forging line is formed at the initial stage in the axial direction of the bar, that is, in parallel with the rolling direction. Usually, the bar in this state is die forged along the shape of the head. As a result, the forged streamline is theoretically pushed outward by forging pressure. This state depends on the shape of the head, and is left to the forging method. However, the actual situation is not necessarily fluid and is not uniformly spread outward. In particular, there is no possibility that the central portion will flow outward and a dead metal state may occur.

  Generally, forged streamlines are along the direction of the bar, and a plurality of forged lines are continuously generated in parallel. In the case of an iron head having a neck portion, the entire material cannot be formed into a head shape with high yield by forging. Since an overhang part exceeding the head shape is inevitably produced, this part is cut out by machining to obtain a regular iron shape. For this reason, a part of the forging line that has been expanded by forging is cut, and all the forging lines by forging are not continuous as originally provided. This means that the endurance strength is reduced as compared with a head in which a forged line is continuously formed.

  In addition, in terms of improving durability, that is, strengthening fatigue strength, various developments have been made as in the above example, but it is necessary to apply a special treatment method such as heat treatment at the time of material or forging, There are still problems in maintaining the toughness of the material. It has been clarified that the presence of the forging line increases the fatigue strength as the material strength in the forging line direction. It is desired to produce a low-cost and durable golf club without impairing the forging line.

  The present invention has been made based on the background as described above, and achieves the following objects. The object of the present invention is to forge with electric heating so as to form a forged wire in a state close to the molded product in advance, and then mold the head by die forging, so that the face portion is thinned and durable It is an object of the present invention to provide a golf club that can be improved and a method for manufacturing the same.

In order to achieve the above object, the present invention employs the following means.
The golf club according to the first aspect of the present invention has a head portion mainly composed of a face portion formed by forging, a toe portion and a heel portion formed over the face portion, and a top portion and a sole portion. In the configuration in which a plurality of forging lines when the face portion is viewed from the front in the striking direction are continuously formed in a direction connecting the ends of the toe portion and the heel portion, the center of the face portion The plurality of forged flow lines are formed in a continuous shape line that protrudes in a convex shape and bulges in the direction crossing the direction connecting the end portions of the toe portion and the heel portion. It is characterized by that.

The golf club of the present invention 2 is characterized in that, in the present invention 1, the forged line formation of the face portion is applied to a head of a wood type golf club. The invention is characterized in that the material of the face portion is a round bar material of α + β type titanium alloy.

A golf club manufacturing method according to a fourth aspect of the present invention is a golf club manufacturing method having a head mainly composed of a face portion, a toe portion formed over the face portion, a heel portion, and a top portion and a sole portion. And heating the intermediate part of the round bar material used as the material of the face part, and compressing and compressing the round bar material in the axial direction during the heating process of the intermediate part, A step of inflating to a larger diameter, a step of removing the both end portions of the round bar material and using the intermediate portion left as a face material, and a plurality of forgings when the face portion is viewed from the front in the striking direction. In the configuration in which the streamline is continuously formed in the direction connecting the ends of the toe portion and the heel portion,
A plurality of forging lines in the center of the face portion, in a direction crossing a direction connecting the ends of the toe portion and the heel portion, and a continuous shape line that protrudes in a convex shape and bulges toward the top portion and the sole portion side; The face part material is die-forged to form the face part.

The method for manufacturing a golf club according to the present invention 5 includes
The step of heating the intermediate part of the round bar material that is the material of the face part is based on electric induction heating.

  The method of manufacturing a golf club according to the sixth aspect of the present invention is the method according to the fourth aspect, wherein the round bar is pressed and compressed in the axial direction during the heating process of the intermediate part, and the intermediate part is expanded to a diameter larger than the diameter of the round bar. Is a process in which the two gripping portions facing each other of the round bar are rotated relative to each other by a predetermined angle, and the torsional deformation is applied to the forging line of the intermediate portion to form the torsional intermediate portion. To do.

  The golf club of the present invention is a round bar material, which is forged by electric heat treatment before die forging. The head portion is provided with a continuous forging line from the toe portion to the heel portion, the top portion and the sole portion. The forged streamline was formed into a shape line that swelled over the part. As a result, by performing die forging after performing forging accompanied by electrothermal compression, the golf club has a head face portion that can be made thin and has improved durability.

FIG. 1 is a front view showing a face portion of a head of a golf club. FIG. 2 is a front view of the face portion schematically showing the form of the forging line that is the configuration of the present invention in a front view. FIG. 3 is an explanatory diagram schematically showing in cross section that the intermediate portion of the round bar is heated and compressed in the axial direction so that the intermediate portion is inflated and the forging lines are arranged on the outside. FIG. 4 is an explanatory view schematically showing a cross section of the face part material structure displaying the forging line. FIG. 5 shows another embodiment, and is an explanatory view schematically showing the configuration of the result of forging by adding a twist to the intermediate part in the heating and compression stage.

  Next, embodiments of the golf club of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view showing a head 1 of a golf club to which the present invention is applied. This example shows a wood-type head 1, and a score line S is formed on the front surface as in a general one. The head 1 mainly includes a face portion 2 that is a hitting portion of a golf ball, a top portion 3 that is a crown portion of the face portion 2, a sole portion 4 below the face portion 2, and a horizontal surface of the face portion 2. It consists of a toe portion 5 at the tip of the direction and a heel portion 6 on the shaft side of the face portion 2.

  Each of these portions are joined individually after being manufactured to constitute the head 1. Further, the end portion of the heel portion 6 constitutes a neck portion 7, and a shaft 8 is attached to the neck portion 7 as a completed golf club. In the case of the wood-type head 1, the face portion 2 is generally processed and manufactured as one component, but the other portions are manufactured as one component in the same manner as the face portion 2, or manufactured together with other portions. May be.

  In general, the wood-type face part 2 is often made of a plate-like metal member. Although there are a wide variety of manufacturing methods, in this example, a method of forging a round bar material of α + β type titanium alloy was applied. Since the metallic characteristics of the α + β type titanium alloy are known, detailed description thereof is omitted. In the present embodiment, Ti-6Al-4V (JIS 60 type, TAB6400) was used.

  The advantage of manufacturing the face part 2 by forging is that the metal particles of the α + β type titanium alloy are densified and made uniform by forging, thereby improving the strength. Further, this α + β-type titanium alloy produces forged lines 9 during forging. The face portion 2 is finally manufactured by die forging. In the die forging, the thickness of the face portion 2 can be partially changed in accordance with the part in the forging process.

  This is a measure for enhancing the golf hitting effect, but the partial thickness difference may be a difference in the shape to be increased or a difference in the portion to be increased. The same applies to the head of an iron golf club. However, in the case of the wood-type head 1, the condition of the face portion 2 is different from that of the iron-type because the hit ball must be moved away. The following embodiment will be described with an example applied to a wood-type head 1.

  In a front view of the face part 2 of the wood-type head 1, the dimensional ratio (aspect ratio) between the top part 3 and the sole part 4 with respect to the dimension between the toe part 5 and the heel part 6 is usually relatively long and oval (elliptical shape). Therefore, securing the strength of the face portion 2 is an important requirement. FIG. 1 is an external view of the head and shows a front view of the face portion. FIG. 2 is an explanatory view schematically showing the face portion 2 on which the forged lines 9 are formed. As will be described later, the forging line 9 has a shape that swells at the center of the face portion 2.

  In this example, the configuration of the head 1 having the face portion 2 in which the direction of the forging line 9 is changed is to improve the durability. The forged wire 9 is also referred to as a metal flow. In the forging process, the metal particles are arranged along the forging direction, which contributes to strengthening of the metal fatigue strength. In the forged product, when a pressure is applied, forged lines 9 are generated and the structure is densified. By using the head 1 in which the forged line 9 is generated, it is possible to secure the strength and reduce the thickness of the face portion 2.

  The bar that is the material of the face portion 2 is generally a rolled material, and a plurality of forged lines 9 are formed in the inside thereof in parallel along the rolling direction. The rolled bar is a high strength material due to the presence of the streamline 9. In the present embodiment, as described above, an α + β type titanium alloy is used as the round bar 10. Conventionally, as shown in the above-described prior art, this rod is formed into a head shape by die forging while maintaining the shape of a predetermined length.

  In the case of the present embodiment, the intermediate part 11 of the round bar 10 is electrically heated, the round bar 10 is pressurized and compressed from the axial direction, and the intermediate part 11 is expanded as shown in FIG. Perform processing. This is so-called upset forging (electric forging), and the forging line 9 is formed while being deformed and expanded outside the round bar 10 by this process. This heat compression treatment is performed by the following three forging steps.

  The conditions for die forging after electro-forging are roughing at 940 ° C., raising at 810 ° C., and correction at 800 ° C. Although it is not necessarily limited to this temperature condition, these become what is called hot forging. After such forging, the intermediate portion 11 becomes the face portion 2 of the completed head 1 through a die forging step after the forging step. The round bar 10 is cut so that the die can be forged to form a face part material 12 as shown in FIG.

  Therefore, the face portion material 12 is a spherical body having a bulging shape in which the forging line 9 projects outward. The forged wire 9 at this time is formed following the shape of the cut bar material 10 while deforming continuously from the end portions 10a, 10b of the bar to the outer portion of the bulge portion at the center. This heat treatment is based on electric induction heating for forging. This induction heating is characterized by good controllability and easy temperature control. In addition, energy conversion efficiency is high, rapid heating is possible, and local heating is possible. This electric induction heating is a processing method suitable for heating the intermediate part of the bar.

  Next, the face material 12 is forged with a die provided along the shape of the face portion 2. The forged line 9 is a shape line that has already continuously extended from the center to the outer shape at this stage. Accordingly, in the die forging in which the face material 12 is extended to the outer shape, the shape of the forged line 9 is not greatly changed during the forming process. The forged stream line 9 extends in a convex shape in the thickness direction in addition to the planar expanded shape. When this is die-forged, the forged lines 9 are in a complicated overlapping state with a curved shape, and the face part 2 is reinforced by press forging. When the forging lines 9 have a curve and overlap, the plurality of forging lines 9 cross and overlap each other, so that the structure in the vicinity of the forging lines 9 is densified to increase the strength. Therefore, the forging line 9 does not extend in a concentrated manner at the center of the face portion 2.

That is, in the conventional case, a material in which a plurality of forging lines are parallel is forged, and particularly in the portion corresponding to the sweet spot of the face portion, the forging lines are concentrated and fluidized. It is difficult to spread outward. As a result, the strength in the forging line direction was partially increased, but the strength in the direction crossing the forging line direction was low. For this reason, heat treatment or the like is performed to increase the strength. This configuration solves this.
Furthermore, the feature of this configuration is that a die forging material having a required size can be formed only by expanding the central portion of the face portion even with a small-diameter round bar. There is no need for a large-diameter round bar that matches the shape of the central portion as in the prior art. As a result, since it is possible to use a small-diameter round bar as a raw material, a small trimming finish can be performed after die forging, resulting in a good yield. This contributes to cost reduction.
More specifically, when a round bar having a diameter of 16 mm and a length of 133 mm is applied, this configuration is installed between the central portions 25 mm (electric forging), and the diameter of the central portion is set to φ20 mm. When this case is compared with the conventional production, a round bar having the same length of φ20 mm is conventionally used as the material for die forging. Therefore, in comparison with this, the weight of the material in this example is 70% as compared with the conventional case. .
This configuration is also characterized in that the center part of the face part can be formed into a thick shape having a different thickness before die forging. Therefore, even if the material has a small diameter, the central portion can be made thick, and therefore the face portion requiring uneven thickness can be easily manufactured.

  With this configuration, the face portion 2 can be configured to have a partially thinned portion in die forging. In addition, the face portion 2 has increased fatigue strength. In the face part 2 obtained by die forging the face part material 12, a plurality of forging lines 9 when viewed from the front in the striking direction are continuous in the direction connecting the ends of the toe part 5 and the heel part 6. And a plurality of forging lines 9 in the center of the face portion are curved toward the top portion 3 and the sole portion 4 in a direction crossing the direction connecting the ends of the toe portion 5 and the heel portion 6. There is a continuous shape line that protrudes and bulges.

  Further, the forging line 9 is a shape line that continuously intersects in the thickness direction. The face part 2 thus molded is finished by trimming such as deburring after die forging. Table 1 shows data obtained by comparing the golf club according to the present embodiment with a conventional golf club that does not perform the process of inflating the intermediate portion in terms of cross-sectional hardness. According to this example, the hardness of the central portion of the face portion tends to be smaller in the present embodiment than in the conventional case. This is determined as a result of arranging the forging line outside the face portion 2. The measurement number indicates the measurement site. Measurement 3 is approximately the center position of the face portion 2.

  Table 2 shows comparison data of durability between the golf club of the present embodiment and a conventional golf club that does not perform the process of inflating the intermediate portion. The present embodiment shows a larger result of the number of impact resistances (the number of impacts, the number of durable shots). That is, it means that the durability is improved, in other words, the fatigue strength tends to increase.

(Other embodiments)
FIG. 5 shows another embodiment, in which an intermediate portion of the round bar 10 is twisted. That is, the round bar 10 in a state in which the intermediate portion 11 is heated to high temperature by electric induction heating is compressed and compressed in the axial direction while the gripping portions 22a and 22b at both ends are rotated relative to each other by a predetermined degree. The intermediate portion 20 is configured. That is, in this configuration, the forged line 23 of the twisted intermediate portion 20 of the round bar 21 is twisted and expanded. The round bar material 21 having this structure is used as a face part material in the same manner as described above to perform die forging to form the face part 2.

  Therefore, when die forging is performed, the central portion of the face portion 2 is formed with a plurality of forging lines 23 twisted as compared with the above example. The molded face portion 2 has a forged line 23 formed continuously in a direction connecting the end portions of the toe portion 5 and the heel portion 6, and is curved and convex on the top portion 3 and sole portion 4 sides. A continuous shape line that projects and bulges is formed, and a plurality of forging lines 23 are also intertwined in the thickness direction of the face portion 2. That is, since the forging lines are mesh-like and the overlapping state in the cross direction increases, the strength of the face portion 2 after die forging is enhanced, which is effective.

DESCRIPTION OF SYMBOLS 1 ... Head 2 ... Face part 3 ... Top part 4 ... Sole part 5 ... Toe part 6 ... Heel part 7 ... Neck part 8 ... Shaft 9 ... Forged wire 10 ... Round bar material 11 ... Middle part 12 ... Face part material

Claims (6)

A face portion (2) formed by forging;
Golf having a head (1) mainly composed of a toe part (5) and a heel part (6) formed over the face part (2), and a top part (3) and a sole part (4). A club,
When the face portion (2) is viewed in front from the striking direction, a plurality of forging lines (9) are continuously formed in a direction connecting the ends of the toe portion (5) and the heel portion (6). In the configuration
The top portion (3) and the top portion (3) in a direction crossing a direction connecting the ends of the toe portion (5) and the heel portion (6) with the plurality of forging lines (9) at the center of the face portion (2). A golf club characterized in that it is a continuous shape line that is curved toward the sole portion (4) and bulges into a convex shape. The golf club according to claim 1,
The golf club is characterized in that the formation of the forged line (9) of the face portion (2) is applied to a head of a wood type golf club. The golf club according to claim 1,
The golf club according to claim 1, wherein the face portion is made of a round bar (10) made of an α + β type titanium alloy. A head mainly composed of a face part (2), a toe part (5) formed over the face part (2), a heel part (6), a top part (3) and a sole part (4). A method of manufacturing a golf club having (1),
Heating the intermediate part (11) of the round bar (10) as the material of the face part (2);
A step of pressing and compressing the round bar (10) in the axial direction during the heating process of the intermediate part (11), and expanding the intermediate part (11) to a diameter larger than the diameter of the round bar (10);
Removing the both ends of the round bar (10) and leaving the intermediate part (11) as a face part material (12);
When the face portion (2) is viewed in front from the striking direction, a plurality of forging lines (9) are continuously formed in a direction connecting the ends of the toe portion (5) and the heel portion (6). In the configuration
The top portion (3) and the sole in a direction crossing the direction connecting the ends of the toe portion (5) and the heel portion (6) with the plurality of forging lines (9) in the center of the face portion (2) A step of forming the face part (2) by die forging the face part material (12) so as to form a continuous shape line which is curved toward the part (4) and protrudes into a convex shape. . In the manufacturing method of the golf club of Claim 4,
A method of manufacturing a golf club, characterized in that the step of heating the intermediate portion (11) of the round bar (10) which is the material of the face portion (2) is by electric induction heating. In the manufacturing method of the golf club of Claim 4,
The step of pressurizing and compressing the round bar (10) in the axial direction during the heating process of the intermediate part (11), and expanding the intermediate part (11) to a diameter larger than the diameter of the round bar (10), Two opposing gripping portions (22a, 22b) of the round bar (10) are rotated relatively different by a predetermined angle, torsional deformation is applied to the forging line of the intermediate portion (11), and the twisted intermediate portion (20) A method for manufacturing a golf club, characterized in that the process is a step to be performed.

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